Infectious keratoconjunctivitis in free-ranging mule deer in Wyoming: a retrospective study and identification of a novel alphaherpesvirus.

We describe the clinicopathologic findings, relative prevalence, and pathogens associated with infectious keratoconjunctivitis in mule deer ( Odocoileus hemionus) in Wyoming. Seventeen cases with ocular lesions were identified among 1,036 mule deer postmortem submissions (1.6%) in an ~16 y period. Sixteen cases were observed in winter and most were in male (15 cases) and juvenile (13 cases) deer. Blindness was the most commonly reported clinical sign (10 cases). A herpesvirus was detected only in the 4 cases of bilateral necrotizing bulbar conjunctivitis. Phylogenetic analysis of glycoprotein amino acid sequences consistently identified this virus as a novel alphaherpesvirus. In 2 of these herpesvirus-positive cases, Actinomyces sp. and Moraxella ovis were also identified. Trueperella pyogenes was identified in 4 cases of unilateral ulcerative keratitis, keratoconjunctivitis, and panophthalmitis. M. ovis was cultured from 3 cases of bilateral conjunctivitis and keratoconjunctivitis. In the remaining cases, isolates included Moraxella bovis (1 case), Staphylococcus sp. and Streptococcus sp. (2), Flavobacterium sp. and Pseudomonas sp. (2), Escherichia coli and Enterobacter sp. (1), and bovine viral diarrhea virus 1 (1). No pathogens were identified in 2 cases. The relative prevalence of keratoconjunctivitis in mule deer in Wyoming appears to be low, and this disease is most commonly associated with infection by a novel alphaherpesvirus, T. pyogenes, and M. ovis.